發(fā)布時間：2018-02-09 15:23

  本文關鍵詞： 風杯式風速傳感器 啟動風速 校準方法 實驗箱 數(shù)值仿真　出處：《南京信息工程大學》2016年碩士論文　論文類型：學位論文

【摘要】：測風儀器中使用最為廣泛的是風杯式風速計,但由于長期在戶外使用,受各種天氣因素影響,風杯組件老化,啟動風速增大,傳統(tǒng)校準啟動風速的方法是將其送到專業(yè)風洞實驗室進行校準,費事費力,達不到現(xiàn)場校準的目的,因此,需采用新的方法對啟動風速進行現(xiàn)場校準。本文針對風杯式風速傳感器啟動風速現(xiàn)場校準的問題,分析了啟動風速影響因素,推導了啟動風速公式,對影響因素中的風壓系數(shù)進行擬合,提出了可以現(xiàn)場測量啟動風速的方法,設計了啟動風速校準實驗箱；實驗箱設計主要包括兩部分工作,一是實驗箱結(jié)構(gòu)設計部分,二是實驗箱硬件電路設計部分。實驗箱結(jié)構(gòu)設計是本文的主體部分及難點,在采用有限元方法進行實驗箱結(jié)構(gòu)設計前,研究了計算流體動力學基礎理論,主要包括：三種基本控制方程,討論常用湍流模型,說明本仿真分析選取S-A湍流模型原因,并確定湍流模型的仿真參數(shù)；闡述對CFD仿真具有關鍵作用的網(wǎng)格劃分,說明本仿真選取非結(jié)構(gòu)化網(wǎng)格原因,詳細論述CFD工作流程,確定本仿真實驗的具體過程。實驗箱結(jié)構(gòu)設計中,利用三維CAD軟件建立多種實驗箱結(jié)構(gòu)模型,選取合適湍流模型、計算模型及仿真參數(shù),采用有限元軟件fluent進行大量數(shù)值仿真實驗,對求解結(jié)果進行可視化處理,對比分析結(jié)構(gòu)不同的風扇動力段,整流段,收縮段對實驗箱內(nèi)流場形態(tài)的影響,選取合適結(jié)構(gòu),在不同風扇轉(zhuǎn)速下對穩(wěn)定出口段流場形態(tài)進行研究,并同時考察整體實驗箱流場形態(tài)。實驗箱硬件電路設計包括：風扇動力段采用PWM直流電機調(diào)速,檢測風速計是否啟動的光電控制開關,以及對實驗箱穩(wěn)定出口段風速實時測量的閉環(huán)恒溫式熱線測風速部分,介紹了各部分的工作原理,給出硬件電路原理圖�？偨Y(jié)實驗箱各部分設計,實驗箱整體結(jié)構(gòu)仿真分析結(jié)果表明：實驗箱出口段流場形態(tài)及速度穩(wěn)定,滿足校準要求,硬件電路功能完整,可以達到現(xiàn)場校準的目的。
[Abstract]:The wind-cup anemometer is the most widely used in the wind measuring instrument. However, due to the long-term outdoor use and the influence of various weather factors, the wind cup component is aging and the starting wind speed is increasing. The traditional method of calibrating start-up wind speed is to send it to the professional wind tunnel laboratory for calibration. A new method is needed to calibrate the starting wind speed. In this paper, the factors influencing the starting wind speed are analyzed, and the formula of the starting wind speed is deduced, aiming at the problem of the field calibration of the starting wind speed of the wind speed sensor. By fitting the wind pressure coefficient of the influencing factors, the method of measuring the starting wind speed on the spot is put forward, and the test box for the calibration of the starting wind speed is designed. The design of the experimental box mainly includes two parts, one is the structural design of the experimental box, and the other is the design of the structure of the experimental box. The second part is the hardware circuit design of the experimental box. The structure design of the experimental box is the main part and the difficulty of this paper. Before adopting the finite element method to design the experimental box structure, the basic theory of computational fluid dynamics (CFD) is studied. It mainly includes three kinds of basic control equations, discusses the common turbulence models, explains why S-A turbulence model is selected in the simulation analysis, and determines the simulation parameters of the turbulence model, and expounds the grid division which plays a key role in the CFD simulation. The reason why unstructured grid is selected in this simulation is explained, the working flow of CFD is discussed in detail, and the concrete process of this simulation experiment is determined. In the structural design of experimental box, many kinds of structural models of experimental box are established by using 3D CAD software, and appropriate turbulence model is selected. In order to calculate the model and the simulation parameters, the finite element software fluent is used to carry out a large number of numerical simulation experiments, and the results are visualized, and the effects of the fan power segment, rectifier section and contraction section of different structure on the flow field in the experimental box are compared and analyzed. At the same time, the flow field pattern of the whole experimental box is investigated. The hardware circuit design of the experimental box includes: the fan power section is regulated by PWM DC motor. The photoelectric control switch for detecting whether the anemometer is started, and the closed loop constant temperature hot-wire wind speed measuring part for the real time measurement of the wind speed at the stable exit section of the experimental box are introduced. The working principle of each part is introduced. The schematic diagram of the hardware circuit is given. The design of each part of the experimental box is summarized. The simulation results of the whole structure of the experimental box show that the flow field form and velocity of the outlet section of the experimental box are stable, the calibration requirements are satisfied, and the function of the hardware circuit is complete. The purpose of field calibration can be achieved.
【學位授予單位】：南京信息工程大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：P414.7;TP212
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本文編號：1498241